Optimizing Nano-Reinforced Cementitious Composites

Cementitious MaterialsNanomaterialsResearch

Optimizing Nano-Reinforced Cementitious Composites

Advances in nanomaterial dispersion and SCM-based binder systems have opened new opportunities for designing high-performance, low-carbon concrete. In this post, I provide a brief overview of my recent work on CNT–calcined clay blends and their impact on mechanical behavior and microstructure.

Why Nanomaterials?

Carbon nanotubes (CNTs) offer:

  • extremely high tensile strength
  • multi-scale crack-bridging capabilities
  • the ability to modify C–S–H chemistry
  • improvements in stiffness and post-crack energy absorption

Even at dosages as low as 0.05–0.1 wt%, CNTs influence both the fresh-state behavior and hardened-state performance of cementitious materials.

Key Findings From Experimental Work

1. Flexural Strength & Modulus

CNT-reinforced metakaolin blends showed:

  • 88% increase in flexural strength
  • 107% increase in elastic modulus
  • significantly enhanced crack-resistance and ductility

These improvements were validated through three-point bending, TPFM fracture testing, and digital microscopy of crack propagation.

2. Rheological Behavior

Adding CNTs can slightly increase yield stress while improving particle suspension stability.
This is important for:

  • pumpability
  • uniform fiber distribution
  • advanced applications such as 3D printing

Experimental Methods

  1. CNT Dispersion
    Acid-functionalization + ultra-sonication to improve hydrophilicity.

  2. Binder Preparation
    Metakaolin replacement levels from 10–20% were tested.

  3. Characterization Tools

    • SEM–EDS
    • XRD
    • FTIR
    • Raman
    • AFM–QNM
    • TGA
    • Nano-CT

Microstructural Insights

CNTs reduce the Ca/Si ratio of C–S–H in the interfacial transition zone, producing a denser, more polymerized silicate structure.

This is a key mechanism behind the observed increase in modulus and toughness.

A Note on Data Processing

Here’s a simple expression used for estimating fracture energy:

G_f = ∫ P(u) du / (b × d)

Where:

  • P(u) is the load–CMOD curve
  • b is specimen width
  • d is specimen depth

Looking Ahead

My next steps include:

  • exploring biochar–CNT hybrid systems
  • automated rheology-log processing
  • scaling nanosystems for concrete applications
  • integrating COâ‚‚-utilizing materials into the same composite framework

If you’d like to follow future updates, feel free to connect with me on
LinkedIn or check back on this site for new posts.